1. Field of the Invention
The present invention relates to an LED decorative light bulb and its manufacturing method, especially to an LED decorative light bulb being of a power-saving, safe and longlife type, and its manufacturing method being simple and cost-effective.
2. Description of Related Art
Decorative light bulbs are a very popular type of decoration throughout the world. An exploded perspective view of a present decorative light bulb is shown in FIG. 5. It comprises a bulb (90), a base (92), and a bulbholder (94). The bulb (90) is made of glass and contains a filament (900) therewithin which connects with a pair of feet (902); the feet (902) extend out of the bulb (90) and electrically connect to the base (92). In assembly, the bulb (90) is installed in the base (92) which then is inserted in the bulbholder (94) which has a cable (940) for electrical power supply.
The basic structure of the aforementioned decorative light bulb has not fundamentally changed since its appearance a long time ago, though many improvements have been provided by manufacturers of related art.
However, the above decorative light bulb has the following shortcomings:
1. power consumption. A power rate of 2.5xcx9c3.5 W of each tungsten-filamented decorative light bulb means that a considerable amount of power is consumed if used on a large scale.
2. danger of electric shock. The use of mains electricity to power the above decorative light bulbs means that the danger of electric shock always presents.
3. breakage. Glass bulbs are obviously fragile.
4. short life span. In fact, most of the above tungsten-filamented decorative light bulbs can be used for only one year.
Among the recently-developed sources of artificial light, LED bulbs are the most suitable one to be used to replace conventional tungsten-filament decorative light bulbs.
An LED bulb and its partially enlarged views are shown in FIGS. 6, 7, and 8. First, a frame (80) as shown in FIG. 6 is formed out of a steel plate. On each top of the frame (80), there is a positive pole (82) and a negative pole (84) which are fixed separately from each other. A cup (840) is formed in the top of the negative pole (84), as shown in FIG. 7. After four steps of plating in the following order: first copperplating, nickeling, second copperplating, and silverplating, the frame (80) is suitable for the assembly of a crystalplate (86). In assembly, molten crystalplate (86) is deposited in the cup (840), and then its lead (860) is attached to the positive pole (82) (as shown in FIG. 8). The whole frame (80) then can be put into a die and an epoxy resin is poured in (not shown in the figure). Finally, the frame (80) is removed from the die and an LED bulb is completed.
The producing procedure may vary from one manufacturer to another but the method they employ and the bulbs they produce are substantially similar. In terms of the manufacturing procedure and structure, none of the bulbs are suitable for use as an Decorative light bulb because of:
1. the high cost of producing equipment. The silverplating is employed to lower the resistance of the frame but its equipment is much more expensive than the one used for producing conventional tungsten bulbs.
2. the high cost of material. The lead (860) of the crystalplate (86) is made of pure gold.
3. the high cost of production. A cup (840) must be formed out on the top of the negative pole (84) which inevitably escalates the cost of producing.
4. the limitation of the structure. The crystalplate (86) has to be molten in the cup (840) of the negative pole (84) and therefore its light will be obscured by the wall of the cup. Furthermore, the crystalplate (86) is always placed at a lower portion of the present LED bulb which, if the LED bulb is put into a base, results in the crystalplate (86) being obscured by the base.
The main objective of the invention is to provide a manufacturing method of an LED decorative light bulb which, by certain arrangement of the manufacturing procedure and selection of materials, is able to greatly lower the manufacturing cost of the LED bulb to a level nearly of that of a tungsten bulb thereby making the LED bulbs commercially effective as Decorative light bulbs.
The other objective of the invention is to provide an LED decorative light bulb which has a crystalplate molten on the top of a negative pole which is higher than the base, and therefore is able to illuminate in all directions and will not be shielded by the base.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.